Motor vehicles may be tested to determine the effects of a side impact on a vehicle door. Such tests are known as a “pole test.” These tests seek to simulate the effects of a crash even involving a side impact on a vehicle door. During the impact of a vehicle subjected to a lateral speed of 20 mph, contact between the occupant and the interior side structure of the vehicle can occur during the first 20 ms.
Vehicles may be equipped with pressure sensors in the doors to detect an early impact and deploy airbags or other restraint systems. The sensors contain elements whose deformations are measured and converted to electrical signals representing pressure values in the door cavities. Pressure sensors are generally effective in measuring deformations in a door cavity indicative of a vehicle crash with a Moving Deformable Barrier (MDB) or pole. However, there are events where deformation of the door cavity can occur, but deployment of side restraints (e.g. side airbags) are not required or desired. For example, deployment of side airbags would typically not be required as a result of slamming a vehicle door, a very low speed parking lot impact, or other such non crash events. To protect against inadvertent deployments, an acceleration sensor may be placed near the vehicle centerline within a Restraints Control Module (RCM) to determine the plausibility of a crash event. The restraint system may be configured to deploy the side airbags or other restraints only if the pressure sensors detect deformation in a door cavity and an accelerometer also detects acceleration exceeding a predefined threshold.